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Full text of "The manufacture and properties of iron and steel"

98
METALLUEGY OF IRON AND STEEL.
razors, watch-springs and other delicate Instruments, no expense is too great in avoiding minute defects, but when these imperfections are few and not of vital importance, there must be a tendency to economize in the cost of the raw material. Second, a heavy heat of open-hearth steel must be cast in masses which are large in comparison with the 4-inch ingot of the crucible works, and the chances for segregation are correspondingly increased, although Table V-B will indicate that with proper precautions there is little danger of trouble.
Some interesting experiments were made by Wahlberg, who took tests from the top and bottom of high-carbon ingots made at four well-known works in Sweden. He found a difference.in the carbon content of the outer skin of the ingot at the top and at the bottom amounting, in the four different ingots, to the following in per cent.:
.13           .06           .09           .09
The differences at the center of the ingot between top and bottom were, respectively, .19, .05, .13 and .09 per cent. Wahlberg gives the carbon as "branded" on the bar. It may be well to compare this with the results obtained by the chemists, and Table V-C gives this information, the maximum and minimum in each case being obtained from the top and bottom of the same ingot.
TABLE V-C. Variations in Swedish Steel.
	Carton per cent.	
Brand.		
	Maximum.	Minimum.
50	46	49
50	53	61
50	49	55
62	59	69
90	88	106
100	88	105
110	107	119
124	114	131
In the Steelton steels, the variations in phosphorus, sulphur, manganese and copper are trifling, while those of silicon are unimportant. In carbon the difference between extremes is 16 points,